Your hair and scalp are just an extension of your face. The number one rule estheticians will tell you is, do not touch your face (especially now that we are in a pandemic!). Same goes for your hair and scalp, the less you touch it, the less greasy it will be.
If you have oily hair, you can bet you have an oily scalp too. Just like your skincare products, look for a shampoo to combat this problem. Aim for a clarifying shampoo or detox shampoo and double cleanse - give yourself not just one, but two shampoos and really get in there. My favorite detox shampoo is, Bumble and Bumble Sunday Shampoo.
When using conditioner, keep it off of your roots. I usually just condition, what would be, my ponytail.
Keep your hair off and out of your face. You can use clips or bobby pins to keep the sides of your hair off of your face. You also want to tie your hair back at night with a scrunchie or wrap it in a braid.
Try using less hair products. It may be possible that you are using a tad too much product. I like to stick to a cocktail of two products - a styling cream/oil and a volumizer. Amika’s Brooklyn Bombshell Blowout Spray is a great volumizer that also helps keep the hair less greasy. For styling cream or oil, apply it on just your ponytail section of your hair, avoiding the roots.
Find a dry shampoo that works for you. There are so many different dry shampoos on the market from organic, colored to match your hair color, to perfume brands making fragrant variations. I like to use a dry shampoo on about day three of my blowout.